Determining the Cause

Chief Complaint: Fever

Pivotal Assessment Finding

History

Acute

Subacute

Chronic

 

Onset & Pattern

  • Acute (<7 days): Often infectious (e.g., flu, COVID-19, UTI).

  • Subacute (1–3 weeks): Could suggest deeper infections (e.g., abscesses), autoimmune disorders.

  • Chronic (>3 weeks): Think of TB, malignancy, autoimmune diseases, or “fever of unknown origin” (FUO).

Associated Symptoms

  • Respiratory symptoms: Cough, sore throat, runny nose → URTI, pneumonia, COVID-19

  • Urinary symptoms: Dysuria, frequency → UTI, pyelonephritis

  • GI symptoms: Diarrhea, abdominal pain → Gastroenteritis, hepatitis

  • Skin findings: Rash, boils → Cellulitis, viral exanthems

  • Musculoskeletal pain: Joint pain → Autoimmune diseases, viral infections

Exposure Risks

  • Travel history: Malaria, dengue, typhoid

  • Animal exposure: Brucellosis, leptospirosis

  • Tick bites: Lyme disease, RMSF

  • Sick contacts: Viral infections (flu, COVID-19)

Medical History

  • Chronic conditions (e.g., diabetes, cancer, HIV)

  • Medications (drug fever, immunosuppressants)

  • Recent surgeries or invasive procedures

2. Perform a Focused Physical Exam

  • Vital signs: Fever pattern, heart rate (relative bradycardia may suggest typhoid)

  • Head/neck: Pharyngitis, lymphadenopathy

  • Chest: Rales, decreased breath sounds (pneumonia, pleural effusion)

  • Abdomen: Tenderness (appendicitis, diverticulitis), hepatosplenomegaly (EBV, malaria)

  • Skin: Rashes, petechiae, injection sites

  • Neurologic: Nuchal rigidity (meningitis), confusion

3. Order Initial Lab Tests

Basic tests help guide further work-up:

Routine labs:

  • CBC with differential: Leukocytosis (bacterial), lymphocytosis (viral)

  • CRP / ESR: General inflammation

  • LFTs: Elevated in hepatitis, sepsis

  • Renal function & electrolytes

  • Urinalysis and urine culture

  • Blood cultures (×2 sets)

  • Chest X-ray

Targeted tests based on clues:

  • Throat swab / Rapid strep test

  • COVID-19 / Influenza test

  • Malaria smear / Dengue serology (if relevant)

  • Autoimmune panel (ANA, RF if autoimmune suspected)

4. Consider More Advanced Testing if Needed

  • CT scans (abdomen/pelvis/chest): If deep infection or abscess suspected

  • Lumbar puncture: If meningitis is suspected

  • Echocardiogram: If endocarditis is a concern

  • HIV test: If unexplained prolonged fever

5. When to Refer or Admit

  • Severe symptoms (e.g., hypotension, altered mental status)

  • Immunocompromised patients

  • Fever > 3 weeks with no clear source

  • Suspected sepsis

Would you like help evaluating a specific case of fever or organizing a checklist?

 

 

 

Fever

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